// Author: Gockner, Simon
// Created: 2021-04-23
// Copyright(c) 2021 SimonG. All Rights Reserved.

using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using Lib.ProcessManaging.Factories;
using Lib.ProcessManaging.Interfaces;

namespace Lib.ProcessManaging
{
    public class ProcessManager : IProcessManager
    {
        private readonly IObservedProcessFactory _observedProcessFactory;

        private Thread? _monitorThread;

        public ProcessManager(IObservedProcessFactory observedProcessFactory)
        {
            _observedProcessFactory = observedProcessFactory;
            Processes = new List<IObservedProcess>();
        }

        public List<IObservedProcess> Processes { get; }
        
        public void Initialize()
        {
            // using ManualResetEvent monitorReadyEvent = new(false);
            _monitorThread = new Thread(Monitor)
            {
                Name = "Process Monitor", 
                IsBackground = true
            };
            
            _monitorThread.Start();
            // monitorReadyEvent.WaitOne();
        }

        private void Monitor(object? state)
        {
            // if (state is not ManualResetEvent monitorReadyEvent)
            //     return;
            //
            // monitorReadyEvent.Set();
            
            foreach (var process in Process.GetProcesses())
            {
                if (Processes.Any(p => p.EqualsProcess(process)))
                    continue;
                
                Processes.Add(_observedProcessFactory.Create(process));
            }

            foreach (IObservedProcess observedProcess in Processes.ToList().Where(p => !Process.GetProcesses().Any(p.EqualsProcess)))
            {
                Processes.Remove(observedProcess);
                observedProcess.Dispose();
            }
            
            Thread.Sleep(1000);
        }

        public void Dispose()
        {
            Processes.ForEach(p => p.Dispose());
            _monitorThread = null;
        }
    }
}